Blood vessels are commonly removed from the body for use in support of coronary artery bypass grafting ("CABG") procedures or the like. In addition, there is a need to take down side branches of vessels to perform an in situ bypass to avoid a fistula. For this purpose, multiple harvesting apparatus and means are known and are commonly used and practiced in the surgical field.
The saphenous vein has been the preferred vessel to be harvested for CABG procedures, although other vessels may be used to support CABG or other grafting procedures. Historically, the saphenous vein has been harvested by making a full length incision along the leg for the length of vein to be removed, accompanied by manual dissection of the vein along its length, transection and ligation of any lateral and deep tissue side branches, followed by transection and ligation of the main trunk of the vein itself and removal of a vein segment for preparation and use in the CABG procedure. Obviously, this type of procedure is quite traumatic and presents a high potential for morbidity and sepsis. Also, the procedure is time-consuming and labor intensive, and consequently is expensive.
To overcome these problems in the prior art, generally minimally invasive or endoscopic vessel removal and harvesting apparatus and means have been developed and are known in the surgical field. One such apparatus and method is disclosed in U.S. Pat. No. 5,373,840, which pertains to a method for harvesting vessels such as a saphenous vein. This procedure utilizes an endoscope having a lumen which permits the surgeon to grasp the saphenous vein by use of a grasping instrument for dissection. The endoscope may be maneuvered along the length of the vein while side branches of the vein are ligated and transected wherever encountered. This method provides for a minimally invasive technique; however, this apparatus and practice of the method provide limited visibility of the saphenous vein and its side branches because viewing is limited to the immediate area directly in front of the endoscope. In addition, illumination within the subcutaneous space created by this type of endoscope is restricted by the light emitted directly at the distal portion of the endoscope. Also, the side branches of the saphenous vein limit the maneuverability of the endoscope since the outer edge of the endoscope body is prevented from advancing along the trunk of the saphenous vein until each sequential side branch is ligated and transected. Once freed, the endoscope is then maneuvered until the next side branch is encountered. It has been found that this type of endoscope, i.e., an endoscope having a lumen, provides a working space which is very restricted because the side walls of the scope body confine the working instrumentation to a limited area.
Furthermore, use of the vessel harvesting apparatus and method described above is typically a "three-handed" approach which, in practice, may require more than one individual. One hand is required to hold and maintain the endoscope, a second hand to hold the free end of the transected vessel, and a third hand to dissect connective tissue from the vessel.
U.S. Pat. No. 4,793,346 shows a process and apparatus for harvesting a vein. Incisions are made at locations at the ends of the vein to be removed. The primary vein is then severed, and a flexible plastic guide is inserted into the vein and manually advanced inside the vein until it is exposed at the distal incision. The surgeon then advances a tube over the exterior of the primary vein, which already contains the interior vein guide. While doing so the surgeon turns and rotates the tube, which supports heated knife blades for severing and electrocauterizing side branches. However, the use of the interior vein guide raises a risk of damaging the endothelium of the blood vessel. In addition, there are no guides to protect the main trunk of the vein from the electrocautery action of the heated knives, or from the knife edges themselves.
Another apparatus and method for endoscopic vessel harvesting is shown in U.S. Pat. No. 5,667,480. This patent shows serial use of an optical dissector followed by an optical retractor for manual dissection, ligation and transection of the side branches and vessels using other equipment.
Other endoscopic apparatus and methods for harvesting of blood vessels are known in the art; however, these other methods and apparatus have not overcome numerous problems, such as possible damage of the main trunk vein during harvesting and the need to manipulate multiple tools or perform multiple time consuming, labor-intensive steps for dissection, retraction and ligation during the harvesting process.
In accordance with the foregoing, one object of the present invention is to provide an apparatus and method for endoscopic harvesting of blood vessels while protecting the main trunk of the vessel from damage so that it may be used successfully to support CABG or other surgical procedures.
Another object of the present invention is to provide an apparatus and method for endoscopic harvesting of blood vessels which minimizes the trauma to the patient associated with surgical incisions.
Yet another object of the present invention is to provide an apparatus and related method for endoscopic harvesting of blood vessels which minimize the labor and time required for harvesting.
Another object of the invention is to relieve deficiencies of prior apparatus and methods that require active dissection and control of side branches during harvesting.
A further object of the present invention is to provide an apparatus and method for endoscopic harvesting of a blood vessel whereby the functions of blunt tissue dissection, transection of side branches and cauterization or ligation of side branches may be performed with a single instrument.
A still further object of the present invention is to provide a method and apparatus for endoscopic harvesting of blood vessels whereby a single instrument may dissect a main trunk line for removal in a single pass over the length of the vessel, thus minimizing the time required for harvesting and the chance for damaging the vessel.